usleep(3) - NetBSD Manual Pages

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USLEEP(3)               NetBSD Library Functions Manual              USLEEP(3)


NAME

     usleep -- suspend execution for interval of microseconds


LIBRARY

     Standard C Library (libc, -lc)


SYNOPSIS

     #include <unistd.h>

     int
     usleep(useconds_t microseconds);


DESCRIPTION

     The usleep() function suspends execution of the calling process until
     either the number of microseconds specified by microseconds have elapsed
     or a signal is delivered to the calling process and its action is to
     invoke a signal catching function or to terminate the process.  The sus-
     pension time may be longer than requested due to the scheduling of other
     activity by the system.

     The microseconds argument must be less than 1,000,000.  If the value of
     microseconds is 0, then the call has no effect.


RETURN VALUES

     On successful completion, usleep() returns 0.  Otherwise, it returns -1
     and sets errno to indicate the error.


ERRORS

     The usleep() function may fail if:

     [EINVAL]           The microseconds interval specified 1,000,000 or more
                        microseconds.


SEE ALSO

     nanosleep(2), sleep(3)


STANDARDS

     The usleep() function conforms to X/Open Portability Guide Issue 4,
     Version 2 (``XPG4.2'').  It later appeared in the POSIX standard, but in
     IEEE Std 1003.1-2004 (``POSIX.1'') it was marked as legacy and the use of
     nanosleep(2) was recommended instead.  The IEEE Std 1003.1-2008
     (``POSIX.1'') revision removed usleep() from the specification.


HISTORY

     The usleep() function appeared in 4.3BSD.

NetBSD 8.0                      April 29, 2010                      NetBSD 8.0